The 4TXC cased coil is a universal model, capable of handling up, down, horizontal, left and right airflow in a 1.5–5 ton unit. American Standard^®‘s all-aluminum coils are designed to work with your outdoor condensing unit or furnace. They are matched in size, efficiency and capacity to ensure optimal performance of your home comfort system. The coil serves as a heat exchanger—working with your heating system in the winter and your cooling system in the summer—featuring a new, enhanced fin design for greater heat transfer.